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Homework Help: Simple harmonic motion of a spring and ball

  1. Aug 11, 2009 #1
    1. The problem statement, all variables and given/known data
    a ball that has been placed on top of a coil spring with a spring constant of 575 N/m and a length (h1) of 25.0 cm. As the ball compresses the spring, it contacts a second spring that has a spring constant of 325 N/m and a length (h2) of 15.0 cm. If the ball is 12.5 cm above the table when it reaches its equilibrium position, what is the mass of the ball?

    2. Relevant equations
    t=2pie√m/k, g= 4pie^2l/T^2

    3. The attempt at a solution
    would i add up the lengths, and add up the acclerations to find the total? in all the above formulas, i dont have enough variables to figure it out.
  2. jcsd
  3. Aug 11, 2009 #2
    You're making it too difficult - nothing is oscillating, so you don't have to solve a simple harmonic oscillator or find an acceleration. In fact, nothing is moving - at the end of the problem, everything is in equilibrium.

    So, when everything is in equilibrium, the sum of all the forces must be equal to .... what?

    What is the downward force on the mass due to gravity?
    What is the upward force on the mass due to Spring 1?
    What is the upward force on the mass due to Spring 2?
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